new IteratorOperation() {
        @Override
        public @Nullable Object execute(Iterator<?> iterator) {
          iterator.remove();
          return null;
        }
      };

  private static final IteratorOperation NEXT_METHOD =
      new IteratorOperation() {
        @Override
        public @Nullable Object execute(Iterator<?> iterator) {
          return iterator.next();
        }

import static java.util.Collections.shuffle;

import java.util.ArrayList;
import java.util.List;
import java.util.Set;
import org.jspecify.annotations.NullUnmarked;
import org.jspecify.annotations.Nullable;

/**
 * Package up sample data for common collections benchmarking.
 *
 * @author Nicholaus Shupe
 */
@NullUnmarked
class CollectionBenchmarkSampleData {
  private final boolean isUserTypeFast;

  /**
   * To avoid infinite recursion, test suites with these marker features won't have derived suites
   * created for them.
   */
  enum NoRecurse implements Feature<@Nullable Void> {
    SUBMAP,
    DESCENDING;

    @Override
    public Set<Feature<? super @Nullable Void>> getImpliedFeatures() {
      return emptySet();
    }
  }

  /**
   * Creates a suite whose map has some elements filtered out of view.
   *

  public @Nullable K floorKey(K key) {
    return keyOrNull(floorEntry(key));
  }

  @Override
  public @Nullable Entry<K, V> ceilingEntry(K key) {
    return tailMap(key, true).firstEntry();
  }

  @Override
  public @Nullable K ceilingKey(K key) {
    return keyOrNull(ceilingEntry(key));
  }

  @Override
  public @Nullable Entry<K, V> higherEntry(K key) {

import com.google.errorprone.annotations.CanIgnoreReturnValue;
import java.io.IOException;
import java.io.Reader;
import java.nio.CharBuffer;
import java.util.ArrayDeque;
import java.util.Queue;
import org.jspecify.annotations.Nullable;

/**
 * A class for reading lines of text. Provides the same functionality as {@link
 * java.io.BufferedReader#readLine()} but for all {@link Readable} objects, not just instances of
 * {@link Reader}.
 *

import com.google.common.annotations.J2ktIncompatible;
import java.io.InvalidObjectException;
import java.io.ObjectInputStream;
import java.io.Serializable;
import java.util.Map.Entry;
import org.jspecify.annotations.Nullable;

/**
 * {@code entrySet()} implementation for {@link ImmutableMap}.
 *
 * @author Jesse Wilson
 * @author Kevin Bourrillion
 */
@GwtCompatible

 * limitations under the License.
 */

package com.google.common.graph;

import com.google.common.collect.ImmutableSet;
import java.util.AbstractSet;
import java.util.Set;
import org.jspecify.annotations.Nullable;

/**
 * Abstract base class for an incident edges set that allows different implementations of {@link
 * AbstractSet#iterator()}.
 */
abstract class IncidentEdgeSet<N> extends AbstractSet<EndpointPair<N>> {

    this.delegateMap = delegateMap;
    this.entries = entries;
    this.size = size;
  }

  @Override
  public int count(@Nullable Object element) {
    return delegateMap.getOrDefault(element, 0);
  }

  @LazyInit private transient @Nullable ImmutableSet<E> elementSet;

  @Override
  public ImmutableSet<E> elementSet() {
    ImmutableSet<E> result = elementSet;

    return CollectionTestSuiteBuilder.using(
            new TestStringCollectionGenerator() {
              @Override
              public Collection<@Nullable String> create(@Nullable String[] elements) {
                List<@Nullable String> list = new ArrayList<>();
                for (String element : elements) {
                  list.add((element == null) ? null : "q" + element);
                }

   * range [0, k) and ignore the remaining elements.
   */
  private final @Nullable T[] buffer;
  private int bufferSize;

  /**
   * The largest of the lowest k elements we've seen so far relative to this comparator. If
   * bufferSize ≥ k, then we can ignore any elements greater than this value.
   */
  private @Nullable T threshold;